Method and apparatus for treating substrates

ABSTRACT

The application describes several methods and an apparatus for treatment of at least partial areas of a substrate. In said methods, at least one liquid is applied to at least one partial area of the substrate and electromagnetic radiation is introduced into this liquid, in order to achieve a desired effect in accordance with the respective method. In one method, radicals are generated in the liquid by means of UV radiation prior to application of the liquid, wherein generation of the radicals occurs directly before applying the liquid to the substrate, such that at least a portion of the radicals reaches the substrate. In one method, in which ions are removed from at least partial areas of the surface of a substrate and near surface layers of said substrate, a liquid, which is heated above ambient temperature is applied to the substrate, in order to form a liquid film on at least a partial area of said substrate, wherein electromagnetic radiation is introduced into said liquid film such that at least a portion of the radiation reaches the substrate surface. In another method for changing the surface characteristics of a substrate having an at least partially hydrophobic substrate surface such that at least a portion of said hydrophobic surface gets a hydrophilic surface characteristic, a liquid is applied to at least the partial area of the surface of the substrate, whose surface characteristic is to be changed, and UV radiation of a predetermined range of wavelength is guided through said liquid onto at least the partial area of the surface of said substrate, whose surface characteristic is to be changed. The methods may be performed in a common apparatus in any desired order in series and/or in parallel.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.13/505,385, which issued as U.S. Pat. No. 9,662,684 B2 on May 30, 2017,and which is based on PCT Application Serial No. PCT/EP2010/001629,filed Mar. 15, 2010, which claims priority from U.S. ProvisionalApplication Ser. No. 61/257,633, filed on Nov. 3, 2009 and GermanApplication Serial No. DE 10 2009 058 982.7, filed on Dec. 18, 2009.

DESCRIPTION

The present Invention relates to a method and an apparatus for treatingsubstrates, wherein a liquid is supplied to at least a partial area ofthe substrate and radiation is introduced into the liquid.

In the field of semiconductors it is known that for example photo maskshave to be exposed to different treatment steps, In particular cleaningsteps, both during their manufacture and during their use in the field.It is in particular known to expose the masks to a wet cleaning process.For such a wet cleaning process it is advantageous if the surface to becleaned has hydrophilic surface characteristics, in order to enablebetter wetting of the surface to be cleaned by the process media appliedthereto. Due to different phenomena, the surface of photo masks,however, is often hydrophobic prior to its cleaning, which may on onehand be caused by the orientation of absorbed water molecules and on theother hand by thin organic layers.

Thus it is known in the field to irradiate the masks prior to a wetcleaning thereof with UV radiation, while the mask is in a gasatmosphere such as nitrogen or an oxygen atmosphere. In this processoften UV radiation having a wavelength of about 172 nm is used.

Such a UV radiation in a gas atmosphere may initiate several differentprocesses such as an oxidation of hydrocarbons at the surface by atomicoxygen, an oxidation of metals at the surface of the substrate by atomicoxygen, the removal of hydrophilic molecular wet layers by photons, andthe activation of adsorbed Ions by UV energy. In particular, ahydrophobic surface area may be changed into a hydrophilic surface area.The photons of the UV radiation, however, often impact unimpeded withhigh energy on the surface of the substrate. This may feed to stressforces and/or relaxation processes in the substrate, in particular infine structures on the substrate.

This may thus lead to the displacement of structures, which maynegatively influence the usability of the substrate.

It is further known to provide a wet treatment after such a preparationof the surface, in which a liquid film is at least locally formed on thesubstrate and UV radiation is introduced into the liquid film. In thisprocess, the liquid and the UV radiation are matched such that amajority of the UV radiation is absorbed in the liquid film in order togenerate radicals therein. In particular, it is known to generatehydroxyl radicals in for example diluted hydrogen peroxide water orozone water O₃—H₂O. Such hydroxyl radicals cause selective dissolutionof organic materials from the substrate surface without harming metallicon the substrate surface if they are present.

Such a method is for example disclosed in US 2006/0207629 A1. Inparticular, a thin liquid film made of for example ozone water, hydrogenperoxide water, ammonia water, a hydrogen peroxide solution, sulfuricacid, organic acids and mixtures thereof is applied. Then, UV radiationis introduced into the liquid film via a window which is transparent toUV radiation and which is in contact with the liquid film, in order togenerate radicals. Again the UV radiation source and the liquid film arematched such that many radicals are generated, such that a highabsorption rate, if possible a complete absorption, of the UV radiationoccurs in the liquid film.

After the removal of the contaminations mentioned above, in particularof organic contaminations, it may be useful to also remove residual ionsfrom the substrate surface. Known methods for this purpose usually useheated liquids, in particular deionized water (DI water) to rinse thesurface. Here, the problem may arise that for a complete removal ofresidual ions either a longer application time of the liquid or a hightemperature of the liquid is required. High temperatures may beproblematic in that the heating process for the liquid may lead tocontaminations therein. This is in particular true when the temperatureis raised close to the boiling point of the respective liquid. In thetreatment of temperature sensitive substrates or substrate layers it isfurthermore possible that the solubility of the Ions is below thedesired value. Prolonging application times for compensating for reducedtemperatures is not desirable in view of efficiency considerations.

Starting from the known treatment methods it is an object of the presentinvention to provide an improved apparatus and an improved method forthe treatment of substrates. In accordance with one aspect of theinvention the generation of a hydrophilic substrate surface should beimproved. In accordance with a further aspect the cleaning of thesubstrate surface should be improved. In accordance with yet anotheraspect of the invention, the removal of ions from the substrate surfaceshould be improved.

In accordance with the present invention one or more of these aspectsmay solved by a method according to claim 1, a method according to claim14, a method according to claims 27, a method according to claim 32, amethod according to claim 37 or a device according to claim 42. Furtherembodiments of the invention are claimed in the respective dependentclaims.

In particular, a method for cleaning of a substrate is provided, inwhich a liquid is applied to at least a partial area of said substrate,wherein prior to applying the liquid to the substrate, radicals aregenerated therein by means of UV radiation, and wherein the generationof said radicals occurs directly before applying the liquid to thesubstrate, such that at least a portion of the radicals reaches thesubstrate. At the same time, by pre-treating the liquid prior toapplying the same to the substrate, it may be ensured that unwantedreactive components such as ozone are destroyed or substantially reducedbefore the liquid reaches the substrate surface.

By generating the radicals directly before applying the liquid to thesubstrate it can be ensured by a targeted direction of flow of themedium having activated radicals therein, that at least a portion ofthese radicals reach the substrate and thus an improved cleaning of thesubstrate surface may be achieved. Preferably, UV radiation may also beintroduced into a liquid film on the substrate formed by the activatedliquid applied to the substrate and containing the radicals orprecursors for radicals, in order to maintain the activation of theradicals and/or to generate further radicals. In so doing, the effectiveduration of the radicals in the liquid may b(c) prolonged, leading to animproved cleaning of the substrate surface.

The UV radiation, which is introduced into the liquid prior to applyingthe same to the substrate and which is introduced into the liquid filmon said substrate may at least partially be emitted by the sameradiation source, thus simplifying the method. For a localized cleaningof surface areas of the substrate it is possible to limit the liquidcontaining the radicals to selected surface areas of the substrate to becleaned.

For generating the radicals UV radiation having for example a wavelengthin the range of 140 nm to 280 nm, depending on the liquid in the rangeof 140 nm to 200 nm may be used, which has a high absorption rate inmost of the liquids. Preferably, the UV radiation in the cited range ofwavelength should be matched to the liquid such that at least 50% ofthis UV radiation, and in particular 80% thereof is absorbed in theliquid.

In one embodiment UV radiation is introduced into the liquid prior toapplying the same to the substrate while the liquid flows along a UVradiation source, wherein on the one hand, the UV radiation is chosensuch that it causes a destruction of the molecular structure of theliquid, in order to facilitate the directly subsequent generation ofradicals possibly by UV radiation. The liquid is thus prepared for anefficient generation of radicals and undesired reactive components inthe liquid are reduced or destroyed prior to the application of theliquid. Thus these components do not contact the substrate surface or doso only in a weaker form. This occurs for example by generating suitedprecursors and intermediate products while the liquid is in motion,because this dynamics facilitates and homogenizes the respectivedestruction or decomposition. The direction of flow of the liquid ischosen such that it flows towards the substrate and such that thegeneration of radicals occurs directly before applying the liquid to thesubstrate. By choosing a suited UV radiation, a pretreatrnent of theliquid on one hand and the generation of radicals on the other hand maybe achieved.

As the liquid is at least one of the following may be used: ozone water,hydrogen water, DI water, H₂O, CO₂—H₂O, DI water having O2 gas dissolvedtherein, NH₄OH, acetic acid, citric add, TMAH, HNO₃, HCl, H₃PO₄ ormixtures thereof. Furthermore, to as is known in the art, hydrogenperoxide solutions, sulfuric add or other organic acids may be used,wherein the decomposition of the media directly before the generation ofthe radicals may make superfluous the use of chemicals which requirespecial disposal. The substrate may for example be one of the following:a photo mask for the manufacture of semiconductors, a semiconductor, inparticular a Si-wafer, a Ge-wafer, a GaAs-wafer or an InP-wafer, a flatpanel substrate and a multi layer ceramic substrate, or any othersubstrate to be cleaned which may for example be used in the manufactureof semiconductors. Such substrates may have different shapes and sizes.During the cleaning at least one of the following is at least partiallyremoved from the substrate by the help of the radicals: carbon,hydrocarbons, organic contaminations as well as organic functionallayers, such as positive resist, negative resist and ion implantedresist, embossing and imprint material, stress buffer and underfillmaterials, lacquers, dyes, bio materials and also bacteria.

In accordance with a further aspect of the invention, a method forremoving ions from the surface of a substrate and near surface layers ofsaid substrate is provided, wherein a liquid which is heated aboveambient temperature is applied onto said substrate, in order to form aliquid film on at least a partial area of said substrate, and whereinelectromagnetic radiation is introduced into said liquid film such thatat least a portion of said radiation reaches the surface of saidsubstrate. The electromagnetic radiation thereby causes increased ionmobility when it hits residual ions on the substrate surface.Furthermore, the electromagnetic radiation may increase the temperatureof the liquid and/or may generate radicals therein, when it is absorbed,both of which may facilitate the removal of ions.

In one embodiment, the liquid is heated at least partially by means ofelectromagnetic radiation immediately prior to and/or during theapplication thereof onto the substrate, thereby little energy lossesoccur, before the thus heated liquid reaches the substrate.Alternatively or additionally, the liquid may be delivered pre-heated tothe point of use before applying electromagnetic radiation. The liquidmay for example be to heated to a temperature in the range betweenambient temperature and the boiling point of the liquid. It is alsopossible to conduct the method under increased pressure and thus heatthe liquid to a higher temperature before it reaches the boiling point.

As the liquid one of the following may for example be used: ozone water,hydrogen water, DI water, H₂O, CO₂—H₂O, DI water having O₂ gas dissolvedtherein or mixtures thereof.

In one embodiment UV radiation, in particular UV radiation having awavelength above 190 nm is introduced into the liquid, at least 50% ofwhich, in particular at least 80% of which reaches the interface betweena surface of the substrate and the liquid film. Alternatively oradditionally IR radiation may be introduced into the liquid film, whichmay for example be used for an in-situ heating of the liquid film. Inthis case at least 50% of the IR radiation should roach the interfacebetween the surface of the substrate and the liquid film. The UVradiation and the IR radiation may be introduced via the same radiationsource. At least a portion of the radiation may generate radicals in theliquid film.

According to a further aspect, a method for changing the surfacecharacteristics of a substrate having an at least partially hydrophobicsubstrate surface is provided, in which at least a portion of saidhydrophobic substrate surface gets an hydrophilic surfacecharacteristic. To achieve this, a liquid is applied to at least thepartial area of the substrate surface, whose surface characteristic isto be changed and UV radiation of a predetermined range of wavelength isguided through said liquid onto at least the partial area of the surfaceof said substrate, whose surface characteristic is to be changed. Due toabsorption of in particular high energy short wave radiation in theliquid, problems with respect to stress forces in the area of thesubstrate surface may be substantially reduced or completely overcome.The liquid also facilitates the removal of the hydrophobic surface layerat low radiation energies compared to the dry condition, thus alsoenabling a further reduction of stress at the substrate surface.

In order to achieve a good transmission through the liquid, thepredetermined range wavelengths of the UV radiation is above 190 nm,wherein at least 80% of the UV radiation within said predeterminedwavelength range should reach the surface of the substrate. As theliquid at least one of the following may be used: ozone water, hydrogenwater, DI water, CO₂-water or mixtures thereof. Other liquids may alsobe used. In particular, DI water may also be used.

The different methods described above, may advantageously combined to acomplete method, wherein individual ones of these methods are conductedsequentially and/or in parallel in the same or also changing liquids. Inparticular, it is possible to conduct these methods in a singleapparatus without the need to handle the substrate between theindividual methods.

In accordance with another aspect, an apparatus for treating substratesis provided, comprising a substrate holder for receiving the substrate,a housing defining a flow chamber having an inlet and an outlet, a firstradiation source, and a unit for generating a relative movement betweensaid substrate holder and said housing. The first radiation source isarranged to emit radiation into said flow chamber and is further capableof emitting UV radiation. The unit for generating the relative movementis capable to arrange said housing with respect to said substrate holdersuch that the outlet is directed towards the substrate holder such thata liquid exiting the outlet directly flows onto a substrate on thesubstrate holder.

Such an apparatus enables the introduction of radiation, in particularUV radiation, into a liquid applied to a substrate via the firstradiation source. This may for example be used, as described in theabove methods, for generating precursors and intermediate products forthe generation of radicals or directly for generating radicals in theliquid. It is, however, also possible to heat the liquid during theapplication thereof onto the substrate.

It is possible that the first radiation source is arranged such that italso emits radiation through said outlet out of the housing. Thisenables introduction of radiation into the liquid not only prior to theapplication thereof onto the substrate but also, thereafter, to maintainan activation of radicals or to generate further radicals. Also, furtherheating of the liquid or maintaining the liquid at a temperature may beachieved. Furthermore, the same radiation source, which is used tointroduce radiation into the liquid prior to the application thereofonto a substrate, may also be used in a simple manner to achievechanging a hydrophobic surface to a hydrophilic surface, or for theremoval of ions from the substrate surface.

In one embodiment, the first radiation source is at least partiallyarranged in said flow chamber. The housing may for example have anoutlet opening in which the first radiation source may be at leastpartially arranged in the outlet opening, in particular, substantiallyin the middle thereof. The outlet opening and the first radiation sourcemay have an extension in length which is greater or at least equal to anextension in width of the substrate to be cleaned, in order to enable acomplete cleaning of the substrate during a single scanning movement ofthe housing relative to the substrate. In one embodiment, the firstradiation source comprises a first lamp, which emits radiation in the UVrange, wherein the first lamp may additionally emit radiation in the IRrange. The first radiation source may additionally comprise at least asecond lamp emitting radiation in a primarily different wavelength rangethan the first lamp. As an example, the second lamp may emit IRradiation, in case the first lamp does not emit IR radiation, or it mayfor example emit UV radiation in a different range of wavelengths. Theradiation source may thus be matched to the requirements of a process byrespectively controlling the first and second lamps. It is also possiblethat the first radiation source has further lamps.

According to one embodiment, a cover is provided between the firstand/or second lamp and the flow chamber in the housing, wherein the atleast one cover is substantially transparent to at least UV radiation.Such a cover enables replacement of individual lamps without the dangerof introducing contaminations into the flow chamber. In this respect,the cover completely surrounds the first and/or second lamp at least inone plane. The material of the cover may for example be quartz.

The first and/or second lamp may be a longitudinal or rod lamp, whichmay extend through the flow chamber and which may provide homogenousradiation throughout the same. The first lamp may inter alia emit UVradiation in the wavelength range between 140 nm and 280 nm, dependingin on the liquid between 140 nm to 200 nm, and in one embodimentprimarily, i.e. more than 50% of UV radiation in this wavelength range.The second lamp may for example emit radiation in the wavelength rangeover 180 nm and/or IR radiation. Hereby different process results may beachieved. The radiation above 180 nm may for example primarily cause adecomposition of certain liquids in the flow chamber, in order tosubsequently facilitate a generation of radicals in the flow chamber bythe radiation in the range between 140 and 280 nm, depending in on theliquid between 140 nm to 200 nm.

Additionally, at least one second radiation source may be providedoutside the flow chamber of the housing such that it emits radiationinto an area adjacent to the outlet of the housing. Such a radiationsource would not primarily emit radiation into the flow chamber, but, ifapplicable, into a liquid film formed on a substrate by liquid exitingthe flow chamber. The second radiation source may primarily emitradiation in a different wavelength range than the first radiationsource, even though it is also contemplated that it emits substantiallythe same radiation. In particular, the second radiation source may emitUV radiation in the wavelength rang(c) above 180 nm and/or IR radiation.

A control unit may be provided, which is capable of individually andindependently controlling the first and second radiation source andpossibly of individual lamps thereof. This enables matching theintroduction of radiation into the liquid applied to a substrate inaccordance with the respective process requirements.

The invention will be explained in more detail herein below withreference to the drawings. In the drawings:

FIG. 1 shows a schematic top view of a treatment apparatus according tothe present invention;

FIG. 2 shows a schematic sectional view of the apparatus of FIG. 1 alongline i-i;

FIG. 3 shows a schematic sectional view similar to FIG. 2 according toan alternative embodiment of the invention;

FIG. 4 shows a schematic sectional view similar to FIG. 2 according to afurther alternative embodiment of the invention;

FIG. 5 shows a schematic sectional view similar to FIG. 2 according toyet another embodiment of the invention.

Any directional references used in the following description, such asabove, below, left or right refers to the drawings and is not to beconstrued as limiting the application, even though it may be a preferredarrangement.

FIG. 1 shows a schematic top view onto an apparatus 1 for treatingsubstrates 2, while FIG. 2 shows a schematic sectional view of theapparatus 1 along the line I-I.

The apparatus 1 basically consists of a receiver for the substrate,which will be called a substrate holder for an application unit 6. Thesubstrate holder 4 and the application unit 6 may be arranged in apressure chamber, which is not shown, in which a positive pressure or anegative pressure may be generated by appropriate means.

The substrate holder 4 is, as may be seen in the drawings, a flatrectangular plate for receiving the also rectangular substrate 2. Thesubstrate holder 4 may have other shapes, which may be matched to theshape of the substrate 2 to be treated. The to substrate holder 4 has adrainage, which is not shown, for liquids, which may be applied via theapplication unit 6 onto the substrate 2.

The application unit 6 consists of a main part 8 and a support part 10,which supports the main part 8 in a movable manner, as is shown by thedouble-headed arrows A is and B. In particular, the support part 10 hasa support arm 12, which is connected on one end to the main part 8, andthe other end of which is connected to a drive, which is not shown. Asis shown by the double-headed arrows A and B, the drive may for exampleprovide a pivotal movement of the support arm 10 and thus the main part8 and/or a linear movement. In this manner, the main part 8 may be movedacross a substrate 2, which is received on said substrate holder 4, inorder to enable treatment of partial areas or the complete surface ofsaid substrate. Furthermore, it is also possible that the support arm 10conducts a lift movement in order to adjust a distance between the mainpart 8 and the surface of a substrate 2 received on the substrate holder4.

Alternatively, or additionally it is also possible to provide a movingmechanism for the substrate holder, in order to provide relativemovement between the substrate 2 and the main part 8.

The main part 8 consists in substance of a housing 14, a fluid port 16and a radiation source 18. The housing 14 has an elongated cuboid shapedbody 20, which defines in its longitudinal extension a flow chamber 22,which in substance extends across the complete lengths of the body 20.The flow chamber 22 has a length extension, which is larger than a widthextension of the substrate 2, in order to be able to apply a liquid tothe substrate across the complete width thereof, as will be explained inmore detail herein below. It is also possible that the flow chamber hasa smaller dimension. The inner surface of the flow chamber 22 isdesigned to have a high reflectivity in particular with respect to UVradiation, while IR radiation may be substantially absorbed.

The flow chamber 20 has a substantially round cross-sectional shape. Theflow chamber 22 is open towards the bottom side of the body 20, suchthat the body defines an outlet opening directed towards the substrate 2to be treated. In an upper portion of the flow chamber 22, a conduit 24is provided in the body 20, which extends in substance parallel to theflow chamber 22. The conduit 24 is fluidly connected to the flow chamber22 at a plurality of locations, in order to conduct fluids into the flowchamber 22 via the conduit 24. In this respect it is noted that theconduit 24 is capable of conducting fluids into the flow chamber 22substantially over the complete length thereof. The conduit 24 is alsoconnected to the fluid port 16.

The fluid port 16 is connected to a conduit, not shown, via which one ormore fluids may be conducted to the fluid port 16. It is possible, thata plurality of fluids may be simultaneously or sequentially conducted tothe fluid port via this conduit. It is also possible to provide aplurality of conduits, via e.g. different fluids may be conducted to thefluid port. As fluids, e.g. liquids may be taken into consideration, butit is also possible to conduct gases to the fluid port, which may e.g.be mixed with a liquid in the fluid port 16 and the conduit 24, beforethey are conducted to the flow chamber 22. In FIG. 2 arrows are shown,which indicate the flow of a fluid from the fluid port 16 via theconduit 24, into the flow chamber 22 and out of the housing 14.

The radiation source 18 has a longitudinally extending shape and extendsalong the complete flow chamber 22, substantially in the middle thereof.The radiation source 18 has a rod lamp 30, which is surrounded by acover 32, which is substantially transparent to the radiation of a lamp30. The rod lamp is of the type, which emits at least UV radiation in apredetermined range of wave length. It is also possible that the rodlamp 30 emits radiation across a broad spectrum of wave lengths and inparticular emits UV radiation and IR radiation.

The cover 32, which may consist for example of quartz glass surroundsthe rod lamp 30 completely within the flow chamber 22 and isolates thesame with respect to fluids in the flow chamber 22. The cover may forexample extend through an end wall of the flow chamber 22 out of thebody 20. This would enable access to the rod lamp 30, for example forreplacement or maintenance purposes, without having to access the flowchamber 22. Due to its arrangement in the flow chamber 22, the cover 32forms together with the inner walls of the flow chamber 22 a flow pathfor fluids conducted into the now chamber z via the conduit 24. Suchfluids new around the cover 32 and thus as a whole around the radiationsource 18. Radiation emitted by the rod lamp 30 is thus introduced intoany fluid flowing along the flow path. Furthermore, the cover 32 extendsbeyond the bottom surface of the body 20 and thus partially extends intoan outlet opening of the body 20. Thus it is possible that radiationemitted from the rod lamp also exits the flow chamber 22 towards thesubstrate holder 4 or onto a substrate 2 thereon. In particular, theradiation may be introduced into a liquid film on the substrate 2, whichis for example formed by a liquid, which flows through the flow chamber22 onto the substrate.

FIG. 3 shows a schematic side view similar to FIG. 2 of an alternativeembodiment of the apparatus 1 for treating substrates 2. When describingthis embodiment, the same reference signs are used as previouslyinasmuch as the same or similar elements are provided.

The apparatus 1 again substantially consists of a substrate holder 4 forreceiving a substrate and an application unit 6. The substrate holdermay be designed ion the same manner as described before with respect toFIGS. 1 and 2.

The application unit 8 again consists of a main part 8 and a supportpart, which is not shown in FIG. 3, which may, however, have the samedesign as previously described with respect to FIGS. 1 and 2. The mainpart 8 again substantially consists of a housing 14, a fluid port 16 anda radiation source 18, wherein the housing 14 and the fluid port mayhave the same design as previously described with respect to FIGS. 1 and2.

The radiation source 18 again has an elongated shape and extendssubstantially in the middle through the flow chamber 22. The radiationsource 18 in this embodiment has rod lamps 30, 30′, which are surroundedby a cover 32, which is substantially transparent to the radiation ofthe rod lamps 30, 30′. The rod lamps 30, 30′ are shown above each otherin FIG. 3, but they may also be arranged in a different manner withinthe cover 32. The rod lamps may be of the same or of different types,wherein at least one of them emits UV radiation in a predetermined rangeof wave length. In particular, it is possible that both rod lamps 30,30′ emit UV radiation in different ranges of wave length. The upper rodlamp 30′ may for example at least partially or primarily emit UVradiation in the wave length range above 180 nm, while the lower rodlamp 30 at least partially or primarily emits UV radiation in the wavelength range of 140 to 280 nm, depending in on the liquid between 140 nmto 200 nm. One or both of the rod lamps 30, 30′ may also emit an amountof IR radiation or other radiation.

The cover 32 surrounds the rod lamps 30, 30′ completely within the flowchamber 22 and isolates the same with respect to fluids in said flowchamber 22. In this respect, the cover 32 may have the same design thecover previously described with respect to FIGS. 1 and 2. Furthermore,it is also possible that further rod lamps are received within the cover32, which may each emit different radiation or also the same radiation.By the arrangement and the choice of rod lamps 30, 30′ a desiredradiation profile (with respect to emitted wave length and spatialdistribution thereof) may be generated within the flow chamber 22 andbeyond the same via the outlet opening of the body 20.

FIG. 4 shows a schematic cross-sectional view similar to FIG. 2 ofanother alternative embodiment of an apparatus 1 for treating substrates2. When describing this embodiment, the same reference signs will beused as previously, inasmuch as the to same or similar elements areprovided.

The apparatus 1 again substantially consists of a substrate holder 4 forreceiving a substrate and an application unit 6. The substrate holder 4may be designed in the same manner as previously described with respectto FIGS. 1 and 2.

The application unit 6 again consists of a main part 8 a support part,which is not shown in FIG. 4, but which may have the same design as onepreviously described with respect to FIGS. 1 and 2.

The main part 8 again consists substantially of a housing 14, a fluidport 16 and a radiation source 18. Additionally, two further radiationsources 40 are provided. The housing 14 may have a similar design as theone previously described with respect to FIGS. 1 and 2, having anelongated cuboid body 20. A flow chamber 22 and a conduit 24 in the body20 have the same design as the ones previously described with respect toFIGS. 1 and 2. This is also true with respect to the fluid port 16.

At the bottom side of the body 20, recesses 42 are provided which extendalong the length of the body on both sides of the outlet opening. Therecesses are dimensioned to at least partially receive the furtherradiation sources 40. The surfaces of the recesses 42 may have areflecting surface for the radiation of the radiation sources 40.

The radiation source 18 may have the same design as one design as onedescribed with respect to FIGS. 1 and 2 or it may also have the designdescribed with respect to FIG. 3.

The radiation sources 40 each comprise a rod lamp extending over thelength of the body 20, which are received in the respective recesses 42of the body 20. Even though this is not shown in FIG. 4, the radiationsources 40 may each comprise a cover which is substantially transparentto the radiation of the rod lamp, which cover isolates the rod lamp withrespect to the ambient, in particular with respect to any liquidsexiting the flow chamber. The rod lamps of the radiation sources 40 maybe of the same or a different type and they can also be of a differenttype to the rod lamps 30, 30′ of the radiation source 18. Instead ofproviding two radiation sources 40, as shown in FIG. 4, it is alsopossible to provide only one radiation source 40.

FIG. 5 shows a schematic sectional view similar to FIG. 2 of a furtherembodiment of an apparatus 1 for treating substrates 2. In thedescription of this embodiment, again the same reference signs are usedas previously, inasmuch as the same or similar elements are provided.

The apparatus 1 again consists substantially of a substrate holder 4,for receiving a substrate and an application unit 6. The substrateholder 4 may be designed in the same manner as previously described withrespect to FIGS. 1 and 2.

The application unit 6 again consists of a main part 8 and a supportpart, which is not shown in FIG. 5. Inasmuch as the main part 8, whichwill be described here in below is capable of completely covering thesubstrate, a movability of the support part may be dispensed with. Onlya distance adjustment may be required, as well as a movability in orderto position the substrate below the main part.

The main part 8 consists in substance of a housing 14, a plurality offluid ports 16 and a plurality of radiation sources 18. The housingconsists of a body 20, which is matched to the shape of the substrate tobe treated. In the body 20, a flow chamber 22 is formed, which is opento the bottom side of the body, wherein the opening corresponds insubstance to the dimensions of the substrate to be treated. The innerwalls of the flow chamber 22 are reflective. The upper side of the flowchamber 22 is connected via a plurality of conduits 24 to a plurality offluid ports 16 (six are shown here).

A plurality of radiation sources 18 (six are shown here) is providedwithin the flow chamber 22, which radiation sources extend in alongitudinal or transverse direction through the flow chamber 22. Thus,different flow paths are formed between the walls of the flow chamber 22and radiation sources 18, as well as between the individual radiationsources. The radiation sources 18 may have the same design as the onesdescribed with respect to FIGS. 1 and 2 or as described with respect toFIG. 3.

Additionally, two further radiation sources 40 are provided. The housing14 has a similar design as the one previously described with respect toFIGS. 1 and 2, having an elongated cuboid shaped body 20, a flow chamber22 and a conduit 24 in the body 20 have the same design, as previouslydescribed with respect to FIGS. 1 and 2. This is also true for fluidport 16.

The rod lamps described above are each connected to a control unit,which is capable of controlling or driving the rod lamps individuallyand independently of the others. Rather than using rod lamps it is alsopossible to use other lamps/radiators which should, however, be capableof providing a substantially homogeneous radiation profile across thelength of the flow chamber.

In the following, operation of the apparatus 1 will be described in moredetail with respect to the Figures.

For the treatment of a surface of the substrate 2, the main part 8 ofthe application unit 6 will be moved over a substrate 2 on the substrateholder 4. If the complete surface of the substrate should be treated themain part 8 may be moved during the treatment described here in belowacross the substrate, unless the embodiment according to FIG. 5 is used,which may completely cover the substrate.

Then, a fluid, in particular a liquid is applied to at least thesurfaces of the substrate to be treated via the fluid ports 16, theconduits 24 and the flow chamber 22. Radiation is introduced into saidfluid via the first radiation sources 18 and/or the radiation sources40. The radiation is chosen such that it directly acts on the substrate,in order to treat the same and/or to act on the fluid for changing thecharacteristics thereof, in order to conduct the desired treatment. Inso doing, different treatment possibilities for the surface of thesubstrate are given, which may be locally limited or may be conducted onthe complete surface of the substrate.

In the following, some of these treatment possibilities are explained inmore detail without being limited to these examples. The treatment of aphoto mask will be given as an example.

First changing of a surface characteristic of a substrate 2 having an atleast partially hydrophobic substrate surface to a hydrophilic substratesurface is described. To achieve the same, a liquid such as DI waterwill be applied as a fluid via the flow chamber 22 onto the substratesurfaces to be treated, in order to form a liquid film on the substrate2. UV radiation will be introduced into this liquid film via theradiation sources 18 or 40, wherein the liquid and the wave length rangeof the UV radiation are matched to each other, such that a substantialportion of the UV radiation reaches the interface between the liquid andthe substrate surface. The UV radiation now acts to change thepreviously hydrophobic substrate surface to a hydrophilic surface.

In order to obtain good transmission of the UV radiation through theliquid film, the wave length range of the UV radiation used here is forexample above 190 nm. In order to provide such a wave length range, acorresponding rod lamp, which emits in this wave length range, may becontrolled or driven, while possibly other lamps are not controlled ordriven. When using the cited wave length range one of the following maybe used as the liquid: ozone-water, hydrogen-water, DI water or mixturesthereof. Other liquids may also be used.

Next, cleaning of substrate surface will be described which surface wasfor example treated to have a hydrophilic surface as described above,and which has contaminations, which may be better removed by interactionwith radicals.

Here, again, a liquid is applied to the surfaces of the substrate 2 tobe cleaned via the flow chamber 22. While the liquid flows around theradiation source 18, UV radiation is emitted into the liquid by theradiation source 18. This radiation causes inter alia the generation ofradicals in the liquid. This generation occurs directly before theliquid is applied to the substrate, such that at least a portion of thethus generated radicals, which have a very short decay time contact thesubstrate 2. Since a radiation of the radiation source 18 is not limitedto the flow chamber 22, it is also introduced into a liquid film whichis formed by the liquid on the substrate 2 and thus generates furtherradicals and/or partially maintains the activation of the alreadygenerated radicals.

By means of a corresponding movement of the application unit 6, it ispossible to selectively clean partial areas or the complete surface ofthe substrate.

The liquid and the radiation introduced therein are again matched toeach other in order to achieve the desired effect. For the generation ofradicals, in particular UV radiation in the wave length range of 140 to280 nm, depending in on the liquid between 140 nm to 200 nm is suited.The UV radiation in the cited wave length range may in particular bematched to the used liquid such that at least 50% of the UV radiationand in particular 80% thereof are absorbed.

Depending on the used liquid, the generation of radicals may also befacilitated by a UV induced decomposition of the liquid, which may occurwhile the liquid flows around the radiation source 18. For this purpose,the UV radiation should be chosen on the one hand such that adestruction of the molecular structure of the liquid is caused, in orderto facilitate a directly following generation of radicals also by meansby UV radiation. UV radiation having a wave length above 180 nm isparticularly suited for such decomposition. In the embodiment of theradiation source 18 shown in FIG. 3 it could thus be advantageous, ifthe upper rod lamp is one, which promotes the decomposition, i.e. emitsUV light having a wave length above 180 nm, while the lower rod lamp isone, which promotes the generation of radicals, i.e. emits UV lighthaving a wave length between 140 and 280 nm, depending in on the liquidbetween 140 nm to 200 nm. Taking DI-water as an example, the wavelengthrange between 140 nm to 200 nm may be suited for the generation ofradicals, while for other liquids, a higher range of wavelength between140 nm to 280 nm may be suited.

These wave length ranges are obviously not binding and may varydepending on the liquid, but are applicable for many of the usually usedliquids for cleaning photo masks such as: ozone-water, hydrogen-water,DI water, H₂O, CO₂-H₂O, DI water having O₂-gas dissolved therein, NH₄OH,organic acids, TMAH, HNO₃, HCl, H₂SO₄ or mixtures thereof.

Finally, a treatment is described in which ions are to be removed fromthe surface or near surface layers of the substrate 2, which was forexample treated as described above.

For this treatment a liquid, which is heated above ambient temperatureis applied via the flow chamber 22 onto the substrate, in order to forma liquid film on at least a partial area of the substrate 2. Radiationis introduced into this liquid film via at least one of the radiationsources 18, 40, wherein the radiation and the liquid are matched to eachother, such that at least a portion of the radiation reaches thesubstrate surface. The electromagnetic radiation causes increased ionmobility, when it hits residual ions on the substrate surface.Furthermore, the radiation, as long as it is absorbed in the liquid mayalso cause a temperature increase and/or the generation of radicals,which may both promote the removal of ions. In particular, the liquidmay be heated directly during the application thereof, for example bymeans of radiation source having a high IR portion. Inasmuch as anincreased temperature of the liquid also increases the solubility of theions in the liquid, the liquid may be heated up to the boiling pointthereof.

As a liquid for example one of the following liquids may be used:ozone-water, hydrogen-water, DI water, H₂O, CO₂-H₂O, DI water havingO₂-gas dissolved therein, or mixtures thereof. DI water is particularlysuited for higher temperatures. As the radiation, in particular UVradiation in the wave length range above 190 nm is suited, which is notso strongly absorbed and which promotes the desired effect of mobilizingand removing ions. IR radiation is also well suited, inasmuch it mayprovide an in-situ heating of the liquid.

The above treatments may be combined as desired and may be conductedsequentially as described or in part or completely simultaneously.

The invention was described here in above with respect to severalembodiments, without being limited to the precise embodiments.

1. An apparatus for treating substrates, said apparatus comprising: asubstrate holder for receiving the substrate; a housing defining a flowchamber having en inlet for a liquid and an outlet opening for theliquid; a first radiation source for emitting UV radiation, the firstradiation source being at least partially arranged in said outletopening to emit radiation into said flow chamber and said outletopening; and a unit for generating a relative movement between saidsubstrate holder and said housing, said unit being configured to arrangesaid housing with respect to said substrate holder such that the outletopening is directed towards the substrate holder such that a liquidexiting the outlet directly flows onto a substrate on the substrateholder.
 2. The apparatus of claim 1, wherein the first radiation sourceis arranged such that it also emits radiation through said outlet out ofthe housing.
 3. The apparatus of claim 1, wherein the first radiationsource is at least partially arranged in said flow chamber.
 4. Theapparatus of claim 1, wherein said housing comprises an outlet openingand said first radiation source is at least partially arranged in saidoutlet opening.
 5. The apparatus of claim 1, wherein the first radiationsource is substantially arranged in the middle of the outlet opening. 6.The apparatus of claim 1, wherein the outlet opening and the firstradiation source have an extension in length which is greater or atleast equal to an extension in width of the substrate to be cleaned. 7.The apparatus of claim 1, wherein the first radiation source comprises afirst lamp, which emits radiation in the UV range.
 8. The apparatus ofclaim 7, wherein the first lamp also emits radiation in the IR range. 9.The apparatus of claim 8, wherein the first radiation source comprisesat least a second lamp emitting radiation in a primarily differentwavelength range than the first lamp.
 10. The apparatus of claim 9,wherein at least one cover is provided between the first and/or secondlamp and the flow chamber, wherein the at least one cover issubstantially transparent to UV radiation.
 11. The apparatus of claim10, wherein the at least one cover completely surrounds the first and/orsecond lamp in one plane.
 12. The apparatus of claim 9, wherein thefirst and/or second lamp is a rod lamp.
 13. The apparatus of claim 9,wherein the first lamp emits UV radiation in the wavelength rangebetween 140 nm to 280 nm.
 14. The apparatus of claim 9, wherein thefirst lamp emits primarily UV radiation in the wavelength range between140 nm and 280 nm.
 15. The apparatus of claim 9, wherein the second lampemits UV radiation in the wavelength range over 180 nm.
 16. Theapparatus of claim 9, wherein the second lamp emits IR radiation. 17.The apparatus of claim 1, wherein al least one second radiation sourceis provided outside the flow chamber of the housing such that it emitsradiation into an area adjacent to the outlet of the housing.
 18. Theapparatus of claim 17, wherein the at least one second radiation sourceemits radiation at a wavelength range that is different than thewavelength range of the first radiation source.
 19. The apparatus ofclaim 17, wherein the at least one second radiation source emits UVradiation at a wavelength range above 180 nm.
 20. The apparatus of claim9, wherein the second radiation source emits IR radiation.
 21. Theapparatus of claim 9, further comprising a control unit configured toindividually and independently control the first and second radiationunits.